Printed circuit board, display apparatus having a printed circuit board and method of manufacturing the printed circuit board

ABSTRACT

A printed circuit board (“PCB”) includes a first pattern structure, a second pattern structure, a third pattern structure, and a fourth pattern structure. The first pattern structure includes a first ground pattern. The second pattern structure includes a first line pattern overlapping the first ground pattern and a second ground pattern electrically insulated from the first line pattern. The third pattern structure includes a third ground pattern overlapping the first line pattern and a second line pattern overlapping the second ground pattern. The fourth pattern structure includes a fourth ground pattern overlapping the second line pattern. Therefore, the PCB may decrease noise.

This application claims priority to Korean Patent Application No.2007-91958, filed on Sep. 11, 2007, and all the benefits accruingtherefrom under 35 USC §119, the contents of which in its entirety areherein incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the present invention relate to a printed circuit board(“PCB”), a display apparatus having the PCB and a method ofmanufacturing the PCB. More particularly, embodiments of the presentinvention relate to a PCB having reduced noise and used for a displayapparatus, a display apparatus having the PCB, and a method ofmanufacturing the PCB.

2. Description of the Related Art

A printed circuit board (“PCB”) generally includes a plurality ofcomponents and a plurality of wirings for electrically connecting onecomponent to another component. As electronic technologies are beingdeveloped, the speeds of signal transfers among components through thewirings of PCBs are being increased, and the response speeds of thecomponents in the PCBs are also being increased.

An electromagnetic field may be generated around a wiring of a PCB whena current flows through the wiring. Electromagnetic fields generatedaround adjacent wirings of the PCB may affect the signals transferredthrough the wirings of the PCB. Therefore, electromagnetic interference(“EMI”) caused by the electromagnetic fields of adjacent wirings mayinterfere with the normal operation of the components of the PCB. Theeffect of the EMI may be increased as the frequencies of the signals areincreased for high-speed operation through the wirings of the PCB.

Signals having high frequencies may be applied to a liquid crystaldisplay (“LCD”) apparatus having a large-sized screen display apparatusand displaying images with high quality. In the LCD apparatus, the EMImay be increased because a swing range of a voltage applied to the LCDapparatus is augmented. For example, a signal transferred between awireless wide area network (“WWAN”) and a notebook computer may includeconsiderable noise due to the EMI when the notebook computer isconnected to the WWAN.

BRIEF SUMMARY OF THE INVENTION

Embodiments of the present invention provide a printed circuit board(“PCB”) capable of reducing noise.

Embodiments of the present invention further provide a display apparatushaving the PCB.

Embodiments of the present invention still further provide a method ofmanufacturing the PCB.

According to exemplary embodiments of the present invention, a PCBincludes a first pattern structure, a second pattern structure, a thirdpattern structure, and a fourth pattern structure. The first patternstructure includes a first ground pattern. The second pattern structureis formed on the first pattern structure. The second pattern structureincludes a first line pattern and a second ground pattern. The secondground pattern is electrically insulated from the first line pattern.The third pattern structure is formed on the second pattern structure.The third pattern structure includes a third ground pattern and a secondline pattern electrically insulated from the third ground pattern. Thefourth pattern structure is formed on the third pattern structure andincludes a fourth ground pattern. The first line pattern may be disposedbetween the first ground pattern and the third ground pattern, and thesecond line pattern may be disposed between the second ground patternand the fourth ground pattern.

In exemplary embodiments of the present invention, the PCB may furtherinclude a first insulation layer, a second insulation layer and a thirdinsulation layer. The first insulation layer is disposed between thefirst pattern structure and the second pattern structure. The secondinsulation layer is disposed between the second pattern structure andthe third pattern structure. The third insulation layer is disposedbetween the third pattern structure and the fourth pattern structure.

In exemplary embodiments of the present invention, the PCB may furtherinclude a controller. The controller is electrically connected to thefirst line pattern and the second line pattern to receive a firstdifferential signal from the first line pattern and apply a seconddifferential signal to the second line pattern.

In exemplary embodiments of the present invention, the PCB may furtherinclude a gamma voltage generator. The gamma voltage generator iscontrolled by the controller to generate a gamma reference voltage. Thefourth pattern structure may further include a third line pattern. Thethird line pattern is electrically insulated from the fourth groundpattern and transfers the gamma reference voltage generated by the gammavoltage generator. The third line pattern may be separated from thesecond line pattern, such as by not overlapping the second line pattern.

According to other exemplary embodiments of the present invention, adisplay apparatus includes a display panel and a PCB. The display paneldisplays an image. The PCB includes a first pattern structure, a secondpattern structure, a third pattern structure, and a fourth patternstructure. The first pattern structure includes a first ground pattern.The second pattern structure is formed on the first pattern structureand includes a first line pattern and a second ground patternelectrically insulated from the first line pattern. The third patternstructure is formed on the second pattern structure and includes a thirdground pattern and a second line pattern electrically insulated from thethird ground pattern. The fourth pattern structure is formed on thethird pattern structure and includes a fourth ground pattern. The firstline pattern may be disposed between the first ground pattern and thethird ground pattern, and the second line pattern may be disposedbetween the second ground pattern and the fourth ground pattern.

According to still other exemplary embodiments of the present invention,in a method of manufacturing a PCB, a first pattern structure is formedon a first surface of a first insulation substrate. The first patternstructure includes a first ground pattern. Then, a second patternstructure is formed on a second surface of the first insulationsubstrate opposite to the first surface. The second pattern structureincludes a first line pattern overlapping the first ground pattern and asecond ground pattern electrically insulated from the first linepattern. Then, a second insulation substrate is disposed on the secondpattern structure. Then, a third pattern structure is formed on thesecond insulation substrate. The third pattern structure includes asecond line pattern overlapping the second ground pattern and a thirdground pattern electrically insulated from the second line pattern andoverlapping the first line pattern. Then, a third insulation substrateis disposed on the third pattern structure. Then, a fourth patternstructure is formed on the third insulation substrate. The fourthpattern structure includes a fourth ground pattern overlapping thesecond line pattern.

According to yet other exemplary embodiments of the present invention, amethod of manufacturing a PCB includes forming a first pattern structureon a first surface of a first insulation substrate, the first patternstructure including a first ground pattern, forming a second patternstructure on a second surface of the first insulation substrate oppositeto the first surface, the second pattern structure including a firstline pattern overlapping the first ground pattern and a second groundpattern electrically insulated from the first line pattern, forming athird pattern structure on a second insulation layer, the third patternstructure including a second line pattern and a third ground pattern,forming a fourth pattern structure on a fourth insulation substrate, thefourth pattern structure including a fourth ground pattern, disposingthe second insulation substrate on the second pattern structure, so thatthe second line pattern and the third ground pattern respectivelyoverlap the second ground pattern and the first line pattern and thesecond insulation substrate is interposed between the second patternstructure and the third pattern structure, and disposing the thirdinsulation substrate on the third pattern structure, so that the fourthground pattern overlaps the second line pattern and the third insulationsubstrate is interposed between the third pattern structure and thefourth pattern structure.

According to exemplary embodiments of the present invention, signal linepatterns are formed in inner pattern structures between outermostpattern structures and ground patterns are formed on and under thesignal line patterns. Therefore, noise generated by electromagneticinterference (“EMI”) may be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill become readily apparent by reference to the following detaileddescription when considered in conjunction with the accompanyingdrawings wherein:

FIG. 1 is an exploded perspective view illustrating an exemplary printedcircuit board (“PCB”) in accordance with exemplary embodiments of thepresent invention;

FIG. 2 is an exploded perspective view illustrating an exemplary PCB inaccordance with exemplary embodiments of the present invention;

FIG. 3 is a cross-sectional view taken along line I-I′ in FIG. 2;

FIG. 4 is a block diagram illustrating an exemplary PCB in accordancewith exemplary embodiments of the present invention;

FIG. 5A is a perspective view illustrating an exemplary displayapparatus in accordance with exemplary embodiments of the presentinvention;

FIG. 5B is a block diagram illustrating an exemplary display apparatusin accordance with exemplary embodiments of the present invention;

FIGS. 6A to 6E are cross-sectional views illustrating an exemplarymethod of manufacturing an exemplary PCB in accordance with exemplaryembodiments of the present invention; and

FIGS. 7A to 7D are cross-sectional views illustrating an exemplarymethod of manufacturing an exemplary PCB in accordance with exemplaryembodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is described more fully hereinafter with referenceto the accompanying drawings, in which embodiments of the presentinvention are shown. The present invention may, however, be embodied inmany different forms and should not be construed as limited to theexemplary embodiments set forth herein. Rather, these exemplaryembodiments are provided so that this disclosure will be thorough andcomplete, and will fully convey the scope of the present invention tothose skilled in the art. In the drawings, the sizes and relative sizesof layers and regions may be exaggerated for clarity.

It will be understood that when an element or layer is referred to asbeing “on,” “connected to” or “coupled to” another element or layer, itcan be directly on, connected or coupled to the other element or layeror intervening elements or layers may be present. In contrast, when anelement is referred to as being “directly on,” “directly connected to”or “directly coupled to” another element or layer, there are nointervening elements or layers present. Like reference numerals refer tolike elements throughout. As used herein, the term “and/or” includes anyand all combinations of one or more of the associated listed items.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements, components, regions,layers and/or sections, these elements, components, regions, layersand/or sections should not be limited by these terms. These terms areonly used to distinguish one element, component, region, layer orsection from another element, component, region, layer or section. Thus,a first element, component, region, layer or section discussed belowcould be termed a second element, component, region, layer or sectionwithout departing from the teachings of the present invention.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the exemplary term “below” can encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the presentinvention. As used herein, the singular forms “a,” “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,elements, components, and/or groups thereof.

Embodiments of the present invention are described herein with referenceto cross-section illustrations that are schematic illustrations ofidealized embodiments (and intermediate structures) of the presentinvention. As such, variations from the shapes of the illustrations as aresult, for example, of manufacturing techniques and/or tolerances, areto be expected. Thus, exemplary embodiments of the present inventionshould not be construed as limited to the particular shapes of regionsillustrated herein but are to include deviations in shapes that result,for example, from manufacturing. For example, an implanted regionillustrated as a rectangle will, typically, have rounded or curvedfeatures and/or a gradient of implant concentration at its edges ratherthan a binary change from implanted to non-implanted region. Likewise, aburied region formed by implantation may result in some implantation inthe region between the buried region and the surface through which theimplantation takes place. Thus, the regions illustrated in the figuresare schematic in nature and their shapes are not intended to illustratethe actual shape of a region of a device and are not intended to limitthe scope of the present invention.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

FIG. 1 is an exploded perspective view illustrating an exemplary printedcircuit board (“PCB”) in accordance with exemplary embodiments of thepresent invention.

Referring to FIG. 1, the PCB includes a first pattern structure 10, asecond pattern structure 20, a third pattern structure 30, and a fourthpattern structure 40.

The first pattern structure 10 includes a low voltage differentialsignal (“LVDS”) line pattern 11 and a first reduced swing differentialsignal (“RSDS”) line pattern 13. The second pattern structure 20includes a ground pattern 21, and the third pattern structure 30includes a gamma line pattern 31. The fourth pattern structure 40includes a second RSDS line pattern 41.

The ground pattern 21 of the second pattern structure 20 may be locatedon a portion of the upper face or substantially the entire upper face ofthe second pattern structure 20. The gamma line pattern 31 of the thirdpattern structure 30 may partially overlap with the second RSDS linepattern 41 of the fourth pattern structure 40 when the PCB is assembled.

The PCB may further include a controller (not illustrated) and a gammavoltage generator (not illustrated). An image signal applied from anexternal graphic device (not illustrated) may be transferred to thecontroller through the LVDS line pattern 11. A control signal appliedfrom the controller may be transferred to a display panel (notillustrated) through the first and the second RSDS line patterns 13 and41. The gamma voltage generator may be controlled by the controller, andthus a gamma voltage may be generated from the gamma voltage generator.The gamma voltage generated from the gamma voltage generator may betransferred to the display panel through the gamma line pattern 31.

The image signal applied from the external graphic device may betransferred to the controller though the LVDS line pattern 11 of thefirst pattern structure 10 and the control signal generated from thecontroller may be transferred to the display panel through the firstRSDS line pattern 13. Hence, electromagnetic interference (“EMI”) may begenerated between the LVDS line pattern 11 and the first RSDS linepattern 13. Further, the LVDS line pattern 11, the first RSDS linepattern 13 and the second RSDS line pattern 41 are located at uppermostand lowermost of portions of the PCB, so that electromagnetic fields mayhave a great effect on all components of the PCB. For example, theelectromagnetic fields may be generated around the LVDS line pattern 11,the first RSDS line pattern 13 and the second RSDS line pattern 41.Furthermore, the gamma line pattern 31 of the third pattern structure 30partially overlaps with the second RSDS line pattern 41 of the fourthpattern structure 40, so that EMI between the gamma line pattern 31 ofthe third pattern structure 30 and the second RSDS line pattern 41 ofthe fourth pattern structure 40 may be generated. As a result,considerable noise may be generated in the above-described PCB accordingto exemplary embodiments of the present invention.

FIG. 2 is an exploded perspective view illustrating an exemplary PCB inaccordance with exemplary embodiments of the present invention. FIG. 3is a cross-sectional view taken along line I-I′ illustrated in FIG. 2.FIG. 4 is a block diagram illustrating an exemplary PCB in accordancewith exemplary embodiments of the present invention.

Referring to FIGS. 2 to 4, a PCB 100 includes a first pattern structure110, a second pattern structure 120, a third pattern structure 130, anda fourth pattern structure 140. The first to fourth pattern structures110, 120, 130, and 140 may be formed from conductive layers including aconductive material, respectively.

The first pattern structure 110 includes a first ground pattern 111. Thefirst pattern structure 110 may have a plate shape. In an exemplaryembodiment of the present invention, the first pattern structure 110 mayhave a plate shape having a first long side, a second long side oppositeto the first long side and two short sides connecting the first longside with the second long side, and the first long side may have astepped cut portion, an inclined portion and a straight portionconnecting the stepped cut portion to the inclined portion. The steppedportion may provide a space at which components of a liquid crystaldisplay (“LCD”) apparatus employing the PCB 100 are located. In anotherexemplary embodiment of the present invention, the first long side ofthe first pattern structure 110 may include an inclined portion and twostraight portions respectively extended from both ends of the inclinedportion. While particular peripheries have been described for the firstpattern structure 110, it should be understood that alternateperipheries would also be within the scope of these embodiments foraccommodating the needs of the apparatuses in which the PCB 100 isemployed. The first ground pattern 111 may be located on a portion ofthe upper face or substantially the entire upper face of the firstpattern structure 110 except for an edge portion of the first patternstructure 110. For example, when the first long side of the firstpattern structure 110 includes the stepped cut portion, the inclinedportion and the straight portion, the first ground pattern 111 may havea rectangular plate form having a width that is smaller than a minimumdistance between the first and the second long sides.

The second pattern structure 120 is disposed under the first patternstructure 110, such that the first pattern structure 110 overlaps thesecond pattern structure 120. The second pattern structure 120 has ashape substantially the same as or similar to that of the first patternstructure 110. Thus, any repetitive explanation concerning the shape ofthe second pattern structure 120 will be omitted. The second patternstructure 120 includes a first line pattern 123 and a second groundpattern 121. The first line pattern 123 of the second pattern structure120 is disposed under the first ground pattern 111 of the first patternstructure 110 when the PCB 100 is assembled. A first differential signalis transferred through the first line pattern 123. For example, thefirst differential signal may be transferred from an external graphicdevice to a controller of the PCB 100 through the first line pattern123. The first line pattern 123 may be variously extended on the secondpattern structure 120. For example, the first line pattern 123 may havea first line portion extended in a first direction and a second lineportion extended from an end of the first line portion in a seconddirection that is different from the first direction. The second groundpattern 121 is electrically insulated from the first line pattern 123.For example, when the first long side of the second pattern structure120 includes the stepped cut portion, the inclined portion and thestraight portion as previously described with respect to the firstpattern structure 110, the second ground pattern 121 may be adjacent tothe second long side of the second pattern structure 120 and the firstline pattern 123 may be closer to the first long side of the secondpattern structure 120 and separated from the second ground pattern 121.

The third pattern structure 130 is disposed under the second patternstructure 120, such that the second pattern structure 120 overlaps thethird pattern structure 130. The third pattern structure 130 has a shapesubstantially the same as or similar to that of the first patternstructure 110. Thus, any repetitive explanation concerning the shape ofthe third pattern structure 130 will be omitted. The third patternstructure 130 includes a third ground pattern 131 and a second linepattern 133. The third ground pattern 131 is disposed under the firstline pattern 123 when the PCB 100 is assembled. The second line pattern133 is electrically insulated from the third ground pattern 131 and isdisposed under the second ground pattern 121 when the PCB 100 isassembled. A second differential signal is transferred through thesecond line pattern 133. For example, the second differential signal istransferred from the controller of the PCB 100 to a display panelthrough the second line pattern 133. The second line pattern 133 may bevariously extended. For example, the second line pattern 133 may beextended in one direction, such as substantially parallel to the secondlong side of the third pattern structure 130. The second line pattern133 may not overlap with the first line pattern 123.

The fourth pattern structure 140 is disposed under the third patternstructure 130, such that the third pattern structure 130 overlaps thefourth pattern structure 140. The fourth pattern structure 140 has ashape substantially the same as or similar to that of the first patternstructure 110. Thus, any repetitive explanation concerning the shape ofthe fourth pattern structure 140 will be omitted. The fourth patternstructure 140 includes a fourth ground pattern 141 and a third linepattern 143. The fourth ground pattern 141 of the fourth patternstructure 140 is disposed under the second line pattern 133 of the thirdpattern structure 130 in an assembled condition of the PCB 100. Thethird line pattern 143 of the fourth pattern structure 140 may notoverlap with the second line pattern 133 of the third pattern structure130. The second line pattern 133 may be spaced from the second long sideof the third pattern structure 130 so as to overlap the fourth groundpattern 141, but not overlap the third line pattern 143. For example,the third line pattern 143 may be separated from the fourth groundpattern 141, such that the second line pattern 133 of the third patternstructure 130 is disposed on a region between the third line pattern 143of the fourth pattern structure 140 and the fourth ground pattern 141 ofthe fourth pattern structure 140. The third line pattern 143 iselectrically insulated from the fourth ground pattern 141. The thirdline pattern 143 may be overlapped by the second ground pattern 121 ofthe second pattern structure 120 and the first ground pattern 111 of thefirst pattern structure 110.

The PCB 100 may further include a first insulation layer 150, a secondinsulation layer 160 and a third insulation layer 170. The first tothird insulation layers 150, 160 and 170 may have a shape substantiallythe same as or similar to that of the first pattern structure 110. Thefirst insulation layer 150 is disposed between the first patternstructure 110 and the second pattern structure 120 to electricallyinsulate the first pattern structure 110 and the second patternstructure 120 from each other. The second insulation layer 160 isdisposed between the second pattern structure 120 and the third patternstructure 130 to electrically insulate the second pattern structure 120and the third pattern structure 130 from each other. The thirdinsulation layer 170 is disposed between the third pattern structure 130and the fourth pattern structure 140 to electrically insulate the thirdpattern structure 130 and the fourth pattern structure 140 from eachother.

The PCB 100 may further include a device controller 180 electricallyconnected to the first line pattern 123 and the second line pattern 133.The device controller 180 receives the first differential signal fromthe external graphic device via the first line pattern 123 and appliesthe second differential signals to the second line pattern 133. Also,the PCB 100 may further include a gamma voltage generator 190 which iscontrolled by the controller 180 to generate a gamma voltage to beapplied to the third line pattern 143.

In exemplary embodiments of the present invention, the PCB 100 receivesan original image signal from an external graphic device and applies animage signal and a control signal to a display panel.

The original image signal may be differentially applied to the PCB 100by a low voltage differential signaling (“LVDS”) method. The firstdifferential signal includes a differential signal form of the originalimage signal. The first differential signal is transferred from theexternal graphic device to the controller 180 through the first linepattern 123. The controller 180 processes the first differential signalto generate an image signal. The controller 180 also generates a controlsignal for controlling the display panel. The image signal and thecontrol signal may be differentially applied to the display panel by areduced swing differential signaling (“RSDS”) method. For example, thecontroller 180 applies the second differential signal, which includesdifferential signal forms of the image signal and/or the control signal,to the second line pattern 133, and the second differential signal istransferred from the controller 180 to the display panel through thesecond line pattern 133. A frequency of the first differential signalmay be the same as that of the second differential signal when the PCB100 receives the first differential signal from the external graphicdevice by the LVDS method and applies the second differential signal tothe display panel by the RSDS method.

In another exemplary embodiment of the present invention, the PCB 100may receive the first differential signal from the external graphicdevice by the LVDS method and apply the second differential signal tothe display panel by a min-LVDS method. A frequency of the firstdifferential signal may be different from that of the seconddifferential signal when the PCB 100 receives the first differentialsignal from the external graphic device by the LVDS method and thenapplies the second differential signal to the display panel by themin-LVDS method.

The gamma voltage generator 190 is controlled by the control signal ofthe controller 180 to generate the gamma voltage. The gamma voltagegenerated from the gamma voltage generator 190 is transferred from thegamma voltage generator 190 to the display panel through the third linepattern 143.

The electromagnetic fields generated around the second line pattern 133and the third line pattern 143, which are generated by signals passingtherethrough, may interfere with each other if the second line pattern133 overlaps with the third line pattern 143. Thus, according toexemplary embodiments of the present invention, an area in which thesecond line pattern 133 overlaps with the third line pattern 143 may beminimized to decrease the EMI between the electromagnetic fields aroundthe second line pattern 133 and the third line pattern 143. In exemplaryembodiments of the present invention, when the second line pattern 133and the third line pattern 143 are viewed from a plan view, the secondline pattern 133 may be separated from the third line pattern 143. Also,the second line pattern 133 may be extended in one direction, such assubstantially parallel to the second long side of the third patternstructure 130, to minimize the area in which the second line pattern 133overlaps with the third line pattern 143.

In the PCB 100 according to exemplary embodiments of the presentinvention, the first line pattern 123 and the second line pattern 133are respectively formed from different layers and ground patterns areformed on and under each of the first line pattern 123 and the secondline pattern 133. For example, first ground pattern 111 is formed on thefirst line pattern 123 and third ground pattern 131 is formed under thefirst line pattern 123. Similarly, second ground pattern 121 is formedon second line pattern 133 and fourth ground pattern 141 is formed undersecond line pattern 133. Therefore, the EMI between the first linepattern 123 and the second line pattern 133 may be prevented. Also, thesecond line pattern 133 does not overlap with the third line pattern 143to prevent the EMI between the second line pattern 133 and the thirdline pattern 143. In addition, the first line pattern 123 and the secondline pattern 133 are formed from inner layers of the PCB 100 which aredisposed between outermost layers of the PCB 100, so that theelectromagnetic fields generated around the first line pattern 123 andthe second line pattern 133 may not have an effect on other componentsof the PCB 100. Therefore, the PCB 100 according to exemplaryembodiments of the present invention may decrease noise.

FIG. 5A is a perspective view illustrating an exemplary displayapparatus in accordance with exemplary embodiments of the presentinvention. FIG. 5B is a block diagram illustrating an exemplary displayapparatus in accordance with exemplary embodiments of the presentinvention. The PCB shown in FIGS. 5A and 5B is substantially the same asor similar to the PCB illustrated in and described with respect to FIGS.2 to 4. Thus, any repetitive explanation concerning the PCB will beomitted.

Referring to FIGS. 5A and 5B, a display apparatus 500 includes a displaypanel 510 and a PCB 520.

The display panel 510 includes a first substrate 511, a second substrate513 and a liquid crystal layer 515.

The first substrate 511 may include a plurality of gate lines G₁, . . ., G_(n) (n is a positive integer greater than 1) and a plurality of datalines D₁, . . . , D_(m) (m is a positive integer greater than 1). Thedata lines D₁, . . . , D_(m) are electrically insulated from the gatelines G₁, . . . , G_(n) and cross the gate lines G₁, . . . , G_(n). Thefirst substrate 511 may further include a plurality of pixels fordisplaying images. A switching element TFT, such as a thin filmtransistor (“TFT”), and a pixel electrode (not illustrated) are formedin each of the pixels.

The second substrate 513 may include a color filter layer (not shown)and a common electrode (not shown) formed on the color filter layer.

The liquid crystal layer 515 is disposed between the first substrate 511and the second substrate 513. The liquid crystal layer 515 includesliquid crystal molecules. The arrangement of the liquid crystalmolecules is changed by an electric field generated between the pixelelectrode of the first substrate 511 and the common electrode of thesecond substrate 513, so that an amount of light passing through theliquid crystal layer 515 may be controlled.

The display apparatus 500 may further include a gate driver 540 and adata driver 530. The gate driver 540 is controlled by the controller 521to apply a gate driving signal to the gate lines G₁, . . . , G_(n). Thedata driver 530 is controlled by the controller 521 to apply an imagesignal to the data lines D₁, . . . , D_(m).

The data driver 530 applies the image signal to the data lines D₁, . . ., D_(m) in response to output signals from the controller 521 and thegamma voltage generator 523. The image signal applied to the data linesD₁, . . . , D_(m) is applied to the pixel electrode via the switchingelement TFT when the switching element TFT is turned on. The switchingelement TFT is turned on when the gate signal is applied to the gatelines G₁, . . . , G_(n).

FIGS. 6A to 6E are cross-sectional views illustrating an exemplarymethod of manufacturing an exemplary PCB in accordance with exemplaryembodiments of the present invention.

Referring to FIG. 6A, a first pattern structure 210 is formed on a lowersurface of a first insulation substrate 250 and a second patternstructure 220 is formed on an upper surface of the first insulationsubstrate 250 opposite to the lower surface. The first pattern structure210 includes a first ground pattern 211. The second pattern structure220 includes a first line pattern 223 and a second ground pattern 221.The first line pattern 223 is formed above the first ground pattern 211,so as to overlap with the first ground pattern 211. The second groundpattern 221 is electrically insulated from the first line pattern 223,such as by being spaced and separated from the first line pattern 223.The first insulation substrate 250 electrically insulates the firstpattern structure 210 and second pattern structure 220 from each other.

Referring to FIG. 6B, a second insulation substrate 260 is disposed onthe second pattern structure 220, such that a lower surface of thesecond insulation substrate 260 faces the second pattern structure 220.

Referring to FIG. 6C, a third pattern structure 230 is formed on anupper surface of the second insulation substrate 260, where the uppersurface is opposite to the lower surface of the second insulationsubstrate 260. The third pattern structure 230 includes a second linepattern 233 and a third ground pattern 231. The second line pattern 233overlaps with the second ground pattern 221. The third ground pattern231 is electrically insulated from the second line pattern 233, such asby being spaced and separated from the second line pattern 233, andoverlaps with the first line pattern 223. The second insulationsubstrate 260 electrically insulates the second pattern structure 220and the third pattern structure 230 from each other.

Referring to FIG. 6D, a third insulation substrate 270 is disposed onthe third pattern structure 230, such that a lower surface of the thirdinsulation substrate 270 faces the third pattern structure 230.

Referring to FIG. 6E, a fourth pattern structure 240 is formed on anupper surface of the third insulation substrate 270, where the uppersurface is opposite to the lower surface of the third insulationsubstrate 270. The fourth pattern structure 240 includes a fourth groundpattern 241 and may further include a third line pattern 243. The fourthground pattern 241 covers the second line pattern 233, such as byoverlapping with the second line pattern 233. The third insulationsubstrate 270 electrically insulates the third pattern structure 230 andthe fourth pattern structure 240 from each other. If provided, the thirdline pattern 243 overlaps an area of the third pattern structure 230where the second line pattern 233 is not formed.

Although not shown, a fourth insulation substrate may be formed on thefourth pattern structure 240. Also, the first to fourth insulationsubstrates 250, 260, 270 may also be termed insulation layers.

A controller (not illustrated) may be further formed on one of the firstto fourth insulation substrates 250, 260, 270. The controller may beelectrically connected to the first line pattern 223 and the second linepattern 233. An original image signal provided by an external graphicdevice (not illustrated) is transferred from the external graphic deviceto the controller through the first line pattern 223. The controllergenerates an image signal and a control signal in response to theoriginal image signal. The image signal and the control signal generatedfrom the controller are transferred from the controller to a displaypanel through the second line pattern 233.

As described above, the fourth pattern structure 240 may further includethe third line pattern 243. Also, a gamma voltage generator (notillustrated) may be further formed on one of the first to fourthinsulation substrates 250, 260, 270. The gamma voltage generator may beelectrically connected to the third line pattern 243.

When viewed from a plan view, the third line pattern 243 may beseparated from the second line pattern 233, so that the electromagneticfields around the second line pattern 233 and the third line pattern 243may not interfere with each other.

FIGS. 7A to 7D are cross-sectional views illustrating an exemplarymethod of manufacturing an exemplary PCB in accordance with exemplaryembodiments of the present invention.

Referring to FIG. 7A, a first pattern structure 310 is formed on a lowersurface of the first insulation substrate 350 and a second patternstructure 320 is formed on an upper surface of the first insulationsubstrate 350 opposite to the lower surface. The first pattern structure310 includes a first ground pattern 311. The second pattern structure320 includes a first line pattern 323 and the second ground pattern 321.The first line pattern 323 is formed above the first ground pattern 311,so as to overlap with the first ground pattern 311. The second groundpattern 321 is electrically insulated from the first line pattern 323,such as being spaced and separated from the first line pattern 323.

Referring to FIG. 7B, a third pattern structure 330 is formed on asecond insulation substrate 360. The third pattern structure 330includes a second line pattern 333 and a third ground pattern 331.

Referring to FIG. 7C, a fourth pattern structure 340 is formed on athird insulation substrate 370. The fourth pattern structure 340includes a fourth ground pattern 341. The fourth pattern structure 340may further include a third line pattern 343.

Referring to FIG. 7D, the second insulation substrate 360 having thesecond line pattern 333 and the third ground pattern 331 formed thereonis disposed on the second pattern structure 320, so that the second linepattern 333 and the third ground pattern 331 are respectively locatedabove the second ground pattern 321 and the first line pattern 323.

Then, the third insulation substrate 370 having the fourth groundpattern 341 formed thereon is disposed on the third pattern structure330, so that the fourth ground pattern 341 is disposed above the secondline pattern 333. When the fourth pattern structure 340 includes thethird line pattern 343, the third line pattern 343 is arranged such thatit does not overlap with the second line pattern 333.

According to the present invention, signal line patterns are formed ininner pattern structures of the PCB between outermost pattern structuresof the PCB and ground patterns are formed on and under the signal linepatterns. Therefore, noise generated by EMI may be prevented.

Also, output line patterns of a controller may not overlap with gammaline patterns so that the noise may be further prevented.

The foregoing is illustrative of the present invention and is not to beconstrued as limiting thereof. Although a few exemplary embodiments ofthe present invention have been described, those skilled in the art willreadily appreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of this invention. Accordingly, all such modifications areintended to be included within the scope of the present invention asdefined in the claims. In the claims, means-plus-function clauses areintended to cover the structures described herein as performing therecited function and not only structural equivalents but also equivalentstructures. Therefore, it is to be understood that the foregoing isillustrative of the present invention and is not to be construed aslimited to the specific embodiments disclosed, and that modifications tothe disclosed embodiments, as well as other embodiments, are intended tobe included within the scope of the appended claims. The presentinvention is defined by the following claims, with equivalents of theclaims to be included therein.

1. A printed circuit board, comprising: a first pattern structureincluding a first ground pattern; a second pattern structure formed onthe first pattern structure, the second pattern structure including: afirst line pattern; and a second ground pattern electrically insulatedfrom the first line pattern; a third pattern structure formed on thesecond pattern structure, the third pattern structure including: a thirdground pattern; and a second line pattern electrically insulated fromthe third ground pattern; and a fourth pattern structure formed on thethird pattern structure, the fourth pattern structure including a fourthground pattern, wherein the first line pattern is disposed between thefirst ground pattern and the third ground pattern, and the second linepattern is disposed between the second ground pattern and the fourthground pattern.
 2. The printed circuit board of claim 1, furthercomprising: a first insulation layer disposed between the first patternstructure and the second pattern structure; a second insulation layerdisposed between the second pattern structure and the third patternstructure; and a third insulation layer disposed between the thirdpattern structure and the fourth pattern structure.
 3. The printedcircuit board of claim 2, further comprising a controller electricallyconnected to the first line pattern and the second line pattern, whereinthe controller receives a first differential signal from the first linepattern and applies a second differential signal to the second linepattern.
 4. The printed circuit board of claim 3, wherein a frequency ofthe first differential signal is substantially same as a frequency ofthe second differential signal.
 5. The printed circuit board of claim 4,wherein the first differential signal comprises a low voltagedifferential signal and the second differential signal comprises areduced swing differential signal.
 6. The printed circuit board of claim3, further comprising a gamma voltage generator controlled by thecontroller to generate a gamma reference voltage.
 7. The printed circuitboard of claim 6, wherein the fourth pattern structure further comprisesa third line pattern electrically insulated from the fourth groundpattern, and the third line pattern transfers the gamma referencevoltage generated by the gamma voltage generator.
 8. The printed circuitboard of claim 7, wherein the third line pattern is separated from thesecond line pattern.
 9. The printed circuit board of claim 8, whereinthe second line pattern is extended substantially in one direction. 10.The printed circuit board of claim 7, wherein the third line patterndoes not overlap with the second line pattern.
 11. A display apparatus,comprising: a display panel displaying an image; and a printed circuitboard including: a first pattern structure including a first groundpattern; a second pattern structure formed on the first patternstructure, the second pattern structure including a first line patternand a second ground pattern electrically insulated from the first linepattern; a third pattern structure formed on the second patternstructure, the third pattern structure including a third ground patternand a second line pattern electrically insulated from the third groundpattern; and a fourth pattern structure formed on the third patternstructure, the fourth pattern structure including a fourth groundpattern, wherein the first line pattern is disposed between the firstground pattern and the third ground pattern, and the second line patternis disposed between the second ground pattern and the fourth groundpattern.
 12. The display apparatus of claim 11, wherein the printedcircuit board further comprises: a first insulation layer disposedbetween the first pattern structure and the second pattern structure; asecond insulation layer disposed between the second pattern structureand the third pattern structure; and a third insulation layer disposedbetween the third pattern structure and the fourth pattern structure.13. The display apparatus of claim 12, wherein the printed circuit boardfurther comprises: a controller electrically connected to the first linepattern and the second line pattern; and a gamma voltage generatorcontrolled by the controller to generate a gamma reference voltage,wherein the controller receives the first differential signal from thefirst line pattern and applies the second differential signal to thesecond line pattern.
 14. The display apparatus of claim 13, wherein thefourth pattern structure further comprises a third line patternelectrically insulated from the fourth ground pattern, and the thirdline pattern transfers the gamma reference voltage generated by thegamma voltage generator.
 15. The display apparatus of claim 14, whereinthe third line pattern is separated from the second line pattern. 16.The display apparatus of claim 14, wherein the third line pattern doesnot overlap with the second line pattern.